Every minute, the equivalent of a rubbish-truck load of plastic goes into the oceans but it does not decompose and will remain forever.

According to the US Smithsonian National Museum of Natural History, one type of albatross in particular - the Laysan - suffers especially badly.

The Laysan albatross catches fish by skimming the surface of the water with its beak, inadvertently picking up floating plastic, which they then feed to chicks.

While the adults can regurgitate their food, the chicks cannot and so it remains in their stomachs.

If people continue to dispose of plastic at the same rate as today, then by 2050 the ocean's plastic could weigh more than the fish.

Image:Prince Charles met a Northern Royal Albatross and its chick in New Zealand in 2005

The plastic can kill sea animals by strangling them or the plastic in an animal's stomach can make it feel full and stop eating, even though it is actually starving.

The plastic also impacts the wider ecosystem: marine life get caught in it, eat it and live in it. It also has a direct impact on our health, acting as a sponge for toxins which can end up in our food.

The interview with Sir David is being released by Greenpeace to mark the launch of Unearthed, the organisation's investigative and environmental news site formerly known as Energydesk.

:: Sky has been running a campaign to make people more aware of the effect plastic has on the world's oceans and to share ways of tackling the problem. To get involved in Sky Ocean Rescue, visit the campaign website here. You can also watch our documentary, A Plastic Tide.